1. Field of the Invention
The present invention relates to an ophthalmic imaging apparatus such as a fundus camera for use in an ophthalmic clinic, particularly to color balance calibration.
2. Related Background Art
A system is known in which an image pickup is used to electronically capture an eye fundus image of an eye to be examined (patient""s eye). This system is exclusive for a specific purpose of eye fundus image pickup. Therefore, a color balance of the image pickup is usually prefixed at a specific value, and cannot be adjusted. The eye fundus image usually has a subtle hue mainly of red and white, and an ophthalmologist diagnoses eye illness based on the image. However, since a large number of electronic apparatuses are disposed between the image pickup and a display or in a periphery of the image pickup, the image hue sometimes changes subtly by electromagnetic influences of the apparatuses. If tone of the obtained eye fundus image changes, it is possibly difficult for the ophthalmologist to diagnose the image.
The color balance can also be adjusted by storing a digital eye fundus image once in a memory and subjecting the image using a software image processing. However, much time is required for the image processing. Additionally, signal level and digital data linearity are deteriorated by quantization noise, and image quality is possibly deteriorated.
Moreover, in order to obtain a desired tone of a final output image, the color balance of a display, printer or another output apparatus itself can also be adjusted. However, when the output apparatus itself is individually adjusted, the color balance of a display portion other than the eye fundus image, or an image from another input apparatus is deteriorated, and the entire image cannot easily be seen.
A main object of the present invention is to improve an ophthalmic imaging apparatus. One of concrete objects of the present invention is to provide an ophthalmic imaging apparatus in which a color balance of a captured image can exactly be calibrated in a short time.
To achieve the objects, according to the present invention, there is provided an ophthalmic imaging apparatus, comprising: an image pickup for capturing an image of an eye to be examined; a memory for storing digital data of the image captured by the image pickup; a display for displaying the image stored in the memory; a first color balancer for adjusting a color balance of the captured image before storing the image in the memory; a second color balancer for adjusting a color balance of the displayed image on the display; and a controller for controlling the first color balancer based on the adjustment of the second color balancer.
Further objects and forms of the present invention will be apparent in the following description of an embodiment.